TWI618192B - Laser processing method for wafer and laser processing device - Google Patents

Abstract

An object of the present invention is to provide a laser processing method and a laser processing device capable of confirming whether a bonding film for die bonding attached to a back surface of a device has a wafer broken along the outer periphery of the device. The invention is a processing method of a wafer that divides a wafer into individual components along a dicing path and attaches a resin film to the back of each component. The processing method of the wafer includes the following steps: A cutting groove is formed along the scribe line to a depth corresponding to the processing thickness of the element; a protective member is attached to the surface of the wafer; the back surface of the wafer is ground so that the dividing groove appears on the back surface, and the wafer is divided into individual parts. Component; attach the adhesive film to the back of the wafer, attach the dicing tape to the adhesive film side and support the outer periphery of the dicing tape with a ring frame, and peel off the protective member attached to the surface of the wafer; The dicing tape side to which the wafer is attached is held by the workpiece holding means of the laser processing device, and the laser light is irradiated from the surface side of the wafer through the dividing groove to the adhesive film, thereby adhering the adhesive along the dividing groove. Film splitting; the next step of film splitting is to detect the plasma light generated when the laser light is irradiated, and record the coordinate values when the plasma light generated when the laser light is irradiated to the component is detected.

Description

Laser processing method for wafer and laser processing device Invention area

The present invention relates to a laser processing method and a laser processing device for a wafer. A wafer having a grid-like dicing track formed on the surface and a component formed in a plurality of areas divided by the dicing track along the dicing track. It can be divided into individual elements, and it can be confirmed whether the adhesive film for die bonding attached to the back surface of each element is broken along the outer periphery of the element.

Background of the invention

For example, in a semiconductor element manufacturing step, ICs, LSIs, and other elements are formed in a plurality of regions divided by a predetermined division line (cut line) forming a grid on the surface of a semiconductor wafer having a substantially circular plate shape, and the element is formed. Each region is divided along the scribe line, thereby manufacturing individual semiconductor elements. Generally, a dicing device is used as a dicing device for dividing a semiconductor wafer, and the dicing device cuts the semiconductor wafer along a dicing path with a cutter having a thickness of about 20 μm. The divided semiconductor elements are widely used in electronic devices such as mobile phones and personal computers by being packaged.

Divided into individual semiconductor devices, a die bonding film (DAF) with a thickness of 20 to 40 μm formed from polyimide resin, epoxy resin, acrylic resin grease, etc. is attached to the back. Grain bonding The subsequent film is bonded to the crystal grains supporting the semiconductor element through the adhesive film by heating. A method of attaching a bonding film for die bonding to a back surface of a semiconductor element is to attach a bonding film to a back surface of a semiconductor wafer, and then attach the semiconductor wafer to a dicing tape through the bonding film. The adhesive film is cut along the scribe line formed on the surface of the semiconductor wafer by a cutter, thereby forming a semiconductor element having the adhesive film on the back surface. (For example, refer to Patent Document 1.)

However, the method disclosed in Japanese Patent Laid-Open No. 2000-182995 has the following problem: when the adhesive film is cut with a semiconductor wafer by a cutter to divide into individual semiconductor elements, it occurs on the back surface of the semiconductor element Defects, or the formation of whisker-like burrs on the film, will be the cause of disconnection during wire bonding.

In recent years, electronic devices such as mobile phones and personal computers have been required to be more lightweight and miniaturized, and thinner semiconductor components have been required. Regarding a technique for thinning a semiconductor element, a division technique called a pre-cut method has been put into practical use. The first cutting method is to form a cutting groove of a predetermined depth (equivalent to the thickness of the completed thickness of the semiconductor element) along the scribe line from the surface of the semiconductor wafer, and then grind the back surface of the semiconductor wafer with the cutting groove formed on the surface. And the technology of making the cutting groove appear on the back surface and dividing it into individual semiconductor elements can process the thickness of the semiconductor elements to 50 μm or less.

However, in the case where the semiconductor wafer is divided into individual semiconductor elements by the first dicing method, it is because a cutting groove having a predetermined depth is formed from the surface of the semiconductor wafer along the scribe line to the back of the semiconductor wafer. The cutting groove is formed on the back surface by grinding, so that an adhesive film for die bonding cannot be mounted on the back surface of the semiconductor wafer in advance. Therefore, because of the first cutting method, when the die is bound to the frame supporting the semiconductor element, it has to be carried out while inserting a bonding agent between the semiconductor element and the die bonding frame, and the junction cannot be smoothly implemented. Problems in the publishing industry.

In order to solve such a problem, a method for manufacturing a semiconductor element has been proposed, in which a bonding film for die bonding is attached to a back surface of a wafer that is divided into individual semiconductor elements by a first cutting method, and the bonding is performed through the bonding layer. The film attaches the semiconductor element to a dicing tape, and thereafter, laser light is irradiated from the surface side of the semiconductor element through a gap between the semiconductor elements to a portion of the adhesive film exposed at the gap, and the adhesive film is placed at the gap. The exposed part is removed. (For example, refer to Patent Document 2.)

Advance technical literature Patent literature

Patent Document 1 Japanese Patent Laid-Open No. 2000-182995

Patent Document 2 Japanese Patent Laid-Open No. 2002-118081

Summary of invention

However, in the processing method described in the aforementioned Patent Document 2, if the gap between the semiconductor elements is insufficient or the semiconductor elements protrude toward the dividing groove side, a part of the laser light is blocked by the semiconductor elements, and the film is not adhered. Cut off parts. Therefore, when a semiconductor element is picked up from a dicing tape, it may happen that the semiconductor element cannot be picked up together with the adhesive film. The problem that the picking step cannot be performed smoothly.

The present invention has been made in view of the above-mentioned facts, and its main technical problem is to provide a laser processing method for a wafer capable of confirming whether a bonding film for die bonding attached to the back surface of a device is broken along the outer periphery of the device and Laser processing device.

In order to solve the above-mentioned main technical problems, according to the present invention, a method for processing a wafer is provided. The dicing path is divided into individual components, and an adhesive film is attached to the back of each component, which is characterized in that it includes the following steps: a dividing groove forming step, from the surface side of the wafer, along the dicing path to form a component corresponding to the processing thickness of the component Deep division groove; protective member attaching step, attaching the protective member to the surface of the wafer on which the dividing groove forming step has been performed; wafer dividing step, performing on the back of the wafer on which the protective member attaching step has been performed Grinding makes the dividing groove appear on the back surface, and divides the wafer into individual components. In the wafer supporting step, a subsequent film is attached to the back surface of the wafer that has been subjected to the wafer dividing step, and a dicing tape is attached to the wafer. Next, on the film side, the outer periphery of the dicing tape is supported by a ring frame, and the protective member attached to the surface of the wafer is peeled off. Then, the film dividing step is performed by attaching Wafer dicing tape side of the embodiment of the wafer support held in a step of the laser processing apparatus of the hand holding the workpiece Section, irradiating laser light from the surface side of the wafer to the adhesive film through the dividing groove, thereby dividing the adhesive film along the dividing groove; the step of dividing the adhesive film is to detect the occurrence of the For the plasma light, the coordinate value when the plasma light generated by the laser light irradiated to the component is detected is recorded.

In addition, according to the present invention, there is provided a laser processing apparatus including: a workpiece holding means for holding the workpiece; and a laser light irradiation means for irradiating laser light to the workpiece holding means. Workpiece; processing feed means to move the workholding means and the laser light irradiation means relative to the processing feed direction (X-axis direction); indexing feed means to make the workholding means The laser light irradiation means moves relative to the index feed direction (Y-axis direction) orthogonal to the processing feed direction (X-axis direction); the X-axis position detection means detects the workpiece holding means. X-axis position; Y-axis position detection means to detect the Y-axis position of the processing object holding means; photographing means to photograph the processing area of the wafer held by the processing object holding means; the laser The processing device is characterized by having a plasma detection means and a control means for detecting the plasma light generated by the laser light irradiating the workpiece held by the workpiece holding means. The control means has a memory based on detection signals from the plasma detection means, the X-axis position detection means, and the Y-axis position detection means, and the coordinate values of the plasma light detected by the plasma detection means are recorded. When the plasma light is detected by the plasma detection means, The detection signals from the position detection means in the X-axis direction and the position detection means in the Y-axis direction determine the coordinate value of the generated plasma light, and record the coordinate value of the generated plasma light in the memory.

In the method for processing a wafer of the present invention, laser light is irradiated to a bonding film through a dividing groove from a surface side of a wafer that is divided into individual elements by a so-called first cutting method, so that the After the film division, the film division step is to detect the plasma light generated when the laser light is irradiated, and to record the coordinate value when the plasma light generated when the laser light is irradiated to the component is detected; therefore, it can be recorded by The coordinate value of the part where the adhesive film is not cut, which is recorded as the processing failure information, is used in the pickup step of the next step, and the problem that the component cannot be picked up with the adhesive film is eliminated.

In addition, based on the coordinate values of the parts where the film is not cut off as the information of the processing failure, the components of the processing failure area can be photographed to check the cause of the processing failure.

In addition, the laser processing apparatus of the present invention includes a plasma detection means for detecting plasma light generated by laser light irradiating the workpiece held by the workpiece holding means, and a control means; The detection signals of the plasma detection means, the X-axis position detection means, and the Y-axis position detection means are a memory in which the coordinate values of the plasma light detected by the plasma detection means are recorded, and the electricity is detected by the plasma detection means. In the case of plasma light, based on the detection signals from the position detection means in the X-axis direction and the position detection means in the Y-axis direction, the coordinate value that generates the plasma light is obtained, and the coordinate value that generates the plasma light is recorded in the memory; therefore, it is possible to By The processing information recorded in the memory is used in the next step, and the next step is performed smoothly.

2‧‧‧ semiconductor wafer

2a‧‧‧ surface

2b‧‧‧ back

3‧‧‧ cutting device

4‧‧‧ protective tape

5‧‧‧Grinding device

6‧‧‧laser processing device

7‧‧‧ chuck table mechanism

8‧‧‧Laser light irradiation unit supporting mechanism

9‧‧‧laser light irradiation unit

10‧‧‧Control

21‧‧‧ Cutting Road

22‧‧‧ Components

31‧‧‧ chuck table for cutting device

32‧‧‧ cutting means

33, 95‧‧‧ shooting methods

51‧‧‧ Collet table of grinding device

51a, 52a, X, X1, Y, 322a ‧‧‧ arrows

52‧‧‧ Grinding Vermiculite

60‧‧‧ static abutment

71, 81, 823, 722‧‧‧ guide rails

72‧‧‧ the first slider

73‧‧‧Second slider

74‧‧‧ cylindrical member

75‧‧‧ Covering station

76‧‧‧ Collet Worktable

77‧‧‧Processing feeding means

78‧‧‧ 1st indexing means

82‧‧‧ movable support abutment

83‧‧‧ 2nd indexing feeding means

91‧‧‧ unit holder

92‧‧‧Laser light irradiation means

93‧‧‧ Condensing point position adjustment means

96‧‧‧ Plasma detection means

100‧‧‧ display means

101‧‧‧ Central Processing Unit (CPU)

102‧‧‧Read Only Memory (ROM)

103‧‧‧ Random Access Memory (RAM)

103a‧‧‧ Poorly processed information storage area

104‧‧‧Input interface

105‧‧‧ output interface

210‧‧‧ divided trench

321‧‧‧ Spindle housing

322‧‧‧rotating spindle

323‧‧‧Cutter

721,731,911

761‧‧‧ Suction Chuck

762‧‧‧ Clamp

771‧‧‧male screw

772‧‧‧Pulse motor

773‧‧‧bearing block

774‧‧‧X-axis position detection method

774a‧‧‧linear scale

774b‧‧‧read head

781‧‧‧Male Screw

782‧‧‧Pulse motor

783‧‧‧bearing block

784‧‧‧Y-axis position detection method

784a‧‧‧linear scale

784b‧‧‧read head

821‧‧‧ Mobile support

822‧‧‧ Attachment

831‧‧‧ male screw

832‧‧‧Pulse motor

921‧‧‧Shell

922‧‧‧ Pulse laser light oscillation means

922a‧‧‧pulse laser oscillator

922b‧‧‧ repeated frequency setting means

923‧‧‧Output adjustment means

924‧‧‧ Concentrator

924a‧‧‧direction conversion mirror

924b, 961a‧‧‧ condenser lens

932‧‧‧Pulse motor

961‧‧‧ Plasma receiving means

961b‧‧‧lens box

962‧‧‧Band Pass Filter

963‧‧‧light detector

DAF‧‧‧ Adhesive film

F‧‧‧ ring frame

G‧‧‧cut trench

T‧‧‧Cutting Tape

W‧‧‧Processed

FIG. 1 is a perspective view showing a semiconductor wafer processed by the wafer processing method of the present invention.

2 (a) and 2 (b) are explanatory diagrams of a step of forming a dividing groove in a method of processing a wafer according to the present invention.

3 (a) and 3 (b) are explanatory diagrams of steps for attaching a protective member in a method for processing a wafer according to the present invention.

4 (a) to (c) are explanatory diagrams of a wafer dividing step in a wafer processing method of the present invention.

5 (a) to (c) are explanatory diagrams of a wafer supporting step in a wafer processing method of the present invention.

6 (a) and 6 (b) are explanatory diagrams showing a second embodiment of a wafer supporting step in a wafer processing method of the present invention.

FIG. 7 is a perspective view of a laser processing apparatus constructed in accordance with the present invention.

8 is a block configuration diagram of a laser ray irradiation means and a plasma detection means provided in the laser processing apparatus shown in FIG. 7.

Fig. 9 is a block diagram showing a configuration of a control means provided in the laser processing apparatus shown in Fig. 7.

FIG. 10 is an explanatory diagram showing a coordinate value of a state in which a wafer having been subjected to a wafer supporting step is held at a chuck table of the laser processing apparatus equipment shown in FIG. 7.

Figures 11 (a) ~ (c) are the film dividing steps in the wafer processing method of the present invention Illustration of the step.

Forms used to implement the invention

Hereinafter, embodiments of a laser processing method and a laser processing apparatus suitable for a wafer of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a perspective view showing a semiconductor wafer as a wafer. The semiconductor wafer 2 shown in FIG. 1 is, for example, a silicon wafer having a thickness of 600 μm, and a plurality of scribe lines 21 are formed in a grid pattern on the surface 2 a. Then, on the surface 2a of the semiconductor wafer 2, elements 22 such as ICs and LSIs are formed in a plurality of areas divided by a plurality of scribe lines 21 forming a grid shape. A procedure for dividing the semiconductor wafer 2 into individual semiconductor elements by a pre-cut method will be described.

The semiconductor wafer 2 is divided into individual semiconductor elements by a first cutting method. First, a predetermined depth (equivalent to the processing thickness of each element) is formed along a scribe line 21 formed on the surface 2a of the semiconductor wafer 2. ) (Divided groove forming step). This divided groove forming step is performed using the cutting device 3 shown in FIG. 2 (a) in the illustrated embodiment. The cutting device 3 shown in FIG. 2 (a) includes a chuck table 31 holding a workpiece, a cutting means 32 for cutting a workpiece held by the chuck table 31, and working on the chuck. A photographing means 33 for photographing the workpiece held on the stage 31. The chuck table 31 is configured to suck and hold the workpiece, and can be moved by a cutting feed mechanism (not shown) in the cutting feed direction indicated by the arrow X in FIG. 2 (a), and The indexing feed mechanism shown in the arrow Y is moved by the indexing feed mechanism (not shown).

The cutting means 32 includes a spindle housing 321 arranged substantially horizontally, a rotating spindle 322 supported by the spindle housing 321 and rotatable freely, and a cutting blade 323 attached to the front end of the rotation spindle 322. A servo motor (not shown) mounted in the main shaft housing 321 rotates in a direction shown by an arrow 322a. Incidentally, the thickness of the cutting blade 323 is set to 30 μm in the illustrated embodiment. The above-mentioned photographing means 33 is attached to the front end of the main shaft case 321, and has an illumination means for illuminating a workpiece, an optical system that captures an area illuminated by the illumination means, and an image that is captured by the optical system. The imaging element (CCD) and the like transmit the image signal to the control means (not shown).

The cutting groove forming step using the cutting device 3 described above is to place the back surface 2b side of the semiconductor wafer 2 on the chuck table 31 as shown in FIG. 2 (a). It operates to hold the semiconductor wafer 2 on the chuck table 31. Therefore, the semiconductor wafer 2 held by the chuck table 31 is the upper surface 2a. The chuck table 31 that attracts and holds the semiconductor wafer 2 in this manner is positioned directly below the imaging means 33 by a cutting feed mechanism (not shown).

When the chuck table 31 is positioned directly under the photographing means 33, an alignment operation is performed, and the semiconductor wafer 2 should be formed along the dicing path 21 by the photographing means 33 and a control means (not shown). Divide the cutting area of the trench. That is, the photographing means 33 and a control means (not shown) perform image processing such as pattern matching for positioning the cutting track 21 and the cutting blade 323 formed in a predetermined direction of the conductor wafer 2, Perform the adjustment of the cutting area (correction step). In addition, about the formation in the semiconductor The dicing track 21 of the bulk wafer 2 extending at right angles to the above-mentioned predetermined direction is also subjected to the adjustment of the cutting area.

After adjusting the detection of the cutting area of the semiconductor wafer 2 held on the chuck table 31 as described above, the chuck table 31 holding the semiconductor wafer 2 is moved to the cutting start position of the cutting area. Then, the cutting blade 323 is rotated in the direction shown by the arrow 322a in FIG. 2 (a) and moved downward to perform the plunging feed. The cut-in feed position is set to a depth position (for example, 50 μm) from the surface of the semiconductor wafer 2 to the depth corresponding to the processed thickness of the element at the outer periphery of the cutting blade 323. After the cutting feed of the cutting blade 323 is performed in this manner, the cutting blade 323 is rotated and the chuck table 31 is cut and fed in a direction indicated by an arrow X in FIG. 2 (a), thereby, as shown in FIG. 2 (b As shown in the figure, a dividing groove 210 (a dividing groove forming step) having a width of 20 μm and a depth corresponding to the processed thickness of the element (for example, 50 μm) is formed along the cutting path 21.

After the above-mentioned dividing groove forming step is performed, the dividing groove 210 having a predetermined depth is formed along the scribe line 21 on the surface 2a of the semiconductor wafer 2 as shown in FIGS. 3 (a) and (b). The surface 2 a (the surface on which the element 22 is formed) of the semiconductor wafer 2 is attached (a protective tape attaching step).

Next, a wafer dividing step is performed, and the back surface 2b of the semiconductor wafer 2 to which the protective tape 4 is attached is ground, so that the dividing groove 210 appears on the back surface 2b, and the semiconductor wafer 2 is divided into individual elements 22. This wafer dividing step is performed using the grinding apparatus 5 shown in FIG. 4 (a). The grinding device 5 shown in FIG. 4 (a) includes a chuck table 51 for holding a workpiece, and a grinding means for grinding a vermiculite 52 for grinding the workpiece held by the chuck table 51. 53. This grinding device 5 is used to implement the wafer In the singulation step, the protective tape 4 side of the semiconductor wafer 2 is placed on the chuck table 51, and the semiconductor wafer 2 is held on the chuck table 51 by actuating a suction means (not shown). Therefore, the semiconductor wafer 2 held by the chuck table 51 is the upper side of the back surface 2b. After the semiconductor wafer 2 is held on the chuck table 51 in this manner, the chuck table 51 is rotated at, for example, 300 rpm in the direction shown by the arrow 51a, and the grinding vermiculite 52 of the grinding means 53 is moved in the direction shown by the arrow 52a. For example, it rotates at 6000 rpm and contacts the back surface 2b of the semiconductor wafer 2 to perform grinding, as shown in FIG. 4 (b), until the dividing groove 210 appears on the back surface 2b. As a result of the grinding until the dividing trench 210 appears, the semiconductor wafer 2 is divided into individual elements 22 as shown in FIG. 4 (c). Incidentally, since the plurality of divided components 22 are attached with the protective tape 4 on the surface, the shape of the semiconductor wafer 2 can be maintained without being scattered.

After implementing the above-mentioned wafer singulation step, a wafer support step is performed, and the bonding film for die bonding is mounted on the back surface 2b of the semiconductor wafer 2 which has been divided into individual elements 22, and is placed on the bonding film side. The dicing tape is attached, and the outer periphery of the dicing tape is supported by a ring frame, and the protective member attached to the surface of the semiconductor wafer 2 is peeled off. In the first embodiment of the wafer supporting step, as shown in FIGS. 5 (a) and 5 (b), a bonding film (DAF) is mounted on the back surface 2b of the semiconductor wafer 2 which has been divided into individual elements 22. (Following the film attaching step). At this time, heating is performed at a temperature of 80 to 200 ° C., and the adhesive film (DAF) is pressed against the back surface 2 b of the semiconductor wafer 2 to be attached. Incidentally, the adhesive film (DAF) is made of an epoxy resin and is made of a film material having a thickness of 20 μm. After the adhesive film (DAF) is mounted on the back surface 2b of the semiconductor wafer 2 in this way, the semiconductor wafer 2 with the adhesive film (DAF) is attached as shown in FIG. 5 (c). The film (DAF) side is attached to the stretchable cutting tape T that has been attached to the ring frame F. Therefore, the protective tape 4 attached to the surface 2a of the semiconductor wafer 2 becomes the upper side. Then, the protective tape 4 attached to the surface 2a of the semiconductor wafer 2 is peeled. Incidentally, although the embodiment shown in FIGS. 5 (a) to (c) shows that the adhesive film (DAF) side of the semiconductor wafer 2 on which the adhesive film (DAF) is attached is attached to the already attached An example of the dicing tape T of the ring frame F. However, the dicing tape T may be attached to the adhesive film (DAF) side of the semiconductor wafer 2 to which the adhesive film (DAF) has been attached, and the dicing tape T may be placed on the outer periphery at the same time. The part is attached to the ring frame F.

Referring to FIG. 6, another embodiment of the wafer supporting step described above will be described.

The embodiment shown in FIG. 6 uses a dicing tape having a bonding film (DAF) in which a bonding film (DAF) is attached to the surface of the dicing tape T in advance. That is, as shown in FIGS. 6 (a) and (b), the back surface 2 b of the semiconductor wafer 2 that has been divided into individual elements 22 is attached to an adhesive film (DAF) attached to the surface of the dicing tape T. The cutting tape T is attached to the outer peripheral portion so as to cover the inner opening portion of the ring frame F. At this time, the adhesive film (DAF) is heated at a temperature of 80 to 200 ° C. and is attached to the back surface 2 b of the semiconductor wafer 2. Incidentally, in the illustrated embodiment, the dicing tape T is made of a polyolefin sheet having a thickness of 95 μm. In the case where a dicing tape having an adhesive film is used in this manner, the adhesive film (DAF) attached to the surface of the dicing tape T is attached to the back surface 2b of the semiconductor wafer 2 and the adhesive film (DAF) is attached. ) Of the semiconductor wafer 2 may be supported by a dicing tape T attached to the ring frame F. Then, attach it to the semiconductor as shown in Fig. 6 (b). The protective tape 4 on the surface 2a of the wafer 2 is peeled off. Incidentally, although the embodiment shown in FIGS. 6 (a) and (b) shows that the back surface 2b of the semiconductor wafer 2 is attached to the adhesive film (DAF) attached to the surface of the dicing tape T, and The dicing tape T is an example in which the outer periphery is attached to the ring frame F, but an adhesive film (DAF) attached to the dicing tape T may be attached to the back surface 2b of the semiconductor wafer 2 and the dicing tape T may be attached at the same time. The outer periphery is attached to the ring frame F.

After implementing the wafer support step described above, a subsequent film division step is performed to hold the dicing tape side of the semiconductor wafer 2 to which the wafer support step has been applied to the workpiece holding means of the laser processing device, and the laser The light ray is irradiated onto the adhesive film (DAF) from the surface side of the semiconductor wafer 2 through the dividing groove 210, thereby dividing the adhering film (DAF) along the dividing groove 210. This subsequent film division step is performed using a laser processing apparatus shown in FIG. 7. The laser processing apparatus 6 shown in FIG. 7 includes a stationary base 60 and a chuck table mechanism 7 mounted on the stationary base so as to be movable in a machining feed direction (X-axis direction) indicated by an arrow X. 60 and hold the workpiece; the laser light irradiates the unit support mechanism 8 in the index feed direction (Y-axis direction) indicated by an arrow Y that can be orthogonal to the direction (X-axis direction) indicated by the above-mentioned arrow X ) Is mounted on the stationary base 60; the laser light irradiation unit 9 is mounted on the laser light irradiation unit support mechanism 8 so as to be movable in the direction (Z-axis direction) indicated by the arrow Z.

The chuck table mechanism 7 has a pair of guide rails 71 and 71 mounted on the stationary base 60 in parallel along a processing feed direction (X-axis direction) indicated by an arrow X; The first slide mounted on the guide rails 71, 71 is moved in the manner shown in the processing feed direction (X-axis direction). Moving block 72; a second sliding block 73 mounted on the first sliding block 72 in a manner capable of moving in the index feed direction (Y-axis direction) indicated by an arrow Y; a cover 75 on the second sliding block The block 73 is supported by a cylindrical member 74, and a chuck table 76 is used as a means for holding a workpiece. The chuck table 76 includes a suction chuck 761 formed of a porous material, and a wafer-shaped semiconductor wafer, for example, a workpiece to be processed is held on the suction chuck 761 by a suction means (not shown). The chuck table 76 configured as described above is rotated by a pulse motor (not shown) mounted in the cylindrical member 74. Incidentally, a clamper 762 for fixing a ring frame described later is mounted on the chuck table 76.

The first sliding block 72 is provided below with a pair of guided grooves 721 and 721 fitted with the pair of guide rails 71 and 71, and on the upper side thereof, there is provided a portion along the arrow Y The indexing feed direction (Y-axis direction) forms a pair of guide rails 722, 722 in parallel. The first sliding block 72 thus configured is fitted with the guided grooves 721 and 721 to a pair of guide rails 71 and 71, and can thus be shown along the pair of guide rails 71 and 71 toward the arrow X. It moves in the machining feed direction (X-axis direction). The chuck table mechanism 7 in the illustrated embodiment has a mechanism for moving the first slide block 72 along a pair of guide rails 71 and 71 in a processing feed direction (X-axis direction) indicated by an arrow X. Processing feed means 77. The processing feed means 77 includes a driving source such as a male screw 771 that is mounted in parallel between the pair of guide rails 71 and 71, and a pulse motor 772 for rotationally driving the male screw 771. One end of the male screw 771 is rotatably supported by a bearing block 773 fixed to the stationary base 60, and the other end is a drive shaft connected to the pulse motor 772. Incidentally, it protrudes below the central portion of the first sliding block 72 A female screw block (not shown) is provided, and the male screw 771 is screwed with a through female screw hole formed in the female screw block. Therefore, the male screw 771 can be driven forward and reverse by the pulse motor 772, so that the first slide block 72 is guided along the guide rails 71 and 71 in the processing feed direction (X-axis direction) indicated by the arrow X. mobile.

The laser processing apparatus in the illustrated embodiment includes an X-axis direction position detection means 774 for detecting the processing feed amount (ie, the X-axis direction position) of the chuck table 76 described above. The X-axis direction position detecting means 774 is a linear scale 774a assembled along the guide track 71 and a read head mounted on the first slider 72 and moving along the linear scale 774a together with the first slider 72. 774b. In the embodiment shown in the figure, the read head 774b of the position detection means 774 in the X-axis direction transmits a pulse signal of one pulse every 1 μm to a control means described later. The control means described later is to detect the machining feed amount (ie, the position in the X-axis direction) of the chuck table 76 by counting the input pulse signals. Incidentally, when the pulse motor 772 is used as the driving source of the processing feed means 77, the detection of the clamp can also be performed by counting the driving pulses of the control means described after outputting the driving signal to the pulse motor 772. The machining feed amount of the head table 76 (that is, the position in the X-axis direction). In addition, when a servo motor is used as the driving source of the processing feed means 77, the pulse signal output from the rotary encoder that detects the rotation number of the servo motor may be transmitted to a control means described later, and the control means The input pulse signals are counted, thereby detecting the machining feed amount of the chuck table 76 (that is, the position in the X-axis direction).

The second sliding block 73 is provided below the second sliding block 73. The first one of the above-mentioned first sliding blocks 72 is fitted to one of the guide rails 722 and 722 and one of the pair of guided grooves 731 and 731 is fitted, and the guided grooves 731 and 731 are fitted to the pair of guides. The guide rails 722 and 722 are movable in the index feed direction (Y-axis direction) indicated by an arrow Y. The chuck table mechanism 7 in the illustrated embodiment has a second slide block 73 for advancing along the guide rails 722 and 722 provided on one pair of the first slide blocks 72 toward the index Y The first index feed means 78 that moves in the feed direction (Y-axis direction). The first indexing feeding means 78 includes a driving source such as a male screw 781 that is mounted in parallel between the pair of guide rails 722 and 722, and a pulse motor 782 for rotationally driving the male screw 781. One end of the male screw 781 is rotatably supported by a bearing block 783 fixed on the first sliding block 72, and the other end is an output shaft drivingly connected to the pulse motor 782. Incidentally, a female screw block (not shown) is protrusively provided below the central portion of the second sliding block 73, and a male screw 781 is screwed with a through female screw hole formed in the female screw block. Therefore, the male screw 781 can be driven forward and reverse by the pulse motor 782, so that the second slide block 73 is guided along the guide rails 722 and 722 in the index feeding direction shown by the arrow Y (the Y-axis direction). )mobile.

The laser processing device in the illustrated embodiment includes a Y-axis direction position detection means 784 for detecting the indexing processing feed amount (ie, the Y-axis direction position) of the second slide block 73. The Y-axis-direction position detection means 784 is read by a linear scale 784a assembled along the guide rail 722 and a second slide block 73 and moved along the linear scale 784a together with the second slide block 73. Head 784b. In the embodiment shown in the figure, the read head 784b of the position detection means 784 in the Y-axis direction is a pulse signal of 1 pulse per 1 μm. The number is transmitted to the control means described later. The control means described later is to detect the index feed of the chuck table 76 (that is, the position in the Y-axis direction) by counting the input pulse signals. Incidentally, when the pulse motor 782 is used as the driving source of the first indexing feeding means 78, the driving pulse of the control means described after outputting the driving signal to the pulse motor 782 can also be counted. The index feed of the chuck table 76 (ie, the position in the Y-axis direction) is detected. In addition, when a servo motor is used as the driving source of the first indexing feeding means 78, a pulse signal output from a rotary encoder that detects the rotation number of the servo motor may be transmitted to a control means described later, and The control means counts the input pulse signals, thereby detecting the indexed feed amount of the chuck table 76 (that is, the position in the Y-axis direction).

The above-mentioned laser light irradiation unit support mechanism 8 has a pair of guide rails 81 and 81 mounted on the stationary base 60 in parallel along the indexed feeding direction (Y-axis direction) indicated by the arrow Y; A movable support base 82 mounted on the guide rails 81 and 81 is moved in a direction shown by an arrow Y. The movable support base 82 is formed by a movable support portion 821 that is movably mounted on the guide rails 81 and 81, and an attachment portion 822 mounted on the movable support portion 821. The attaching portion 822 is provided with a pair of guide rails 823 and 823 extending in a direction (Z-axis direction) indicated by an arrow Z in parallel on one side. The laser beam irradiation unit support mechanism 8 in the illustrated embodiment has a movable support base 82 along a pair of guide rails 81 and 81 in the index feed direction (Y-axis direction) indicated by an arrow Y. ) The second indexing feeding means 83 is moved. The second indexing feeding means 83 includes a pair of A driving source such as a male screw 831 between the guide rails 81 and 81, and a pulse motor 832 for rotationally driving the male screw 831. One end of the male screw 831 is rotatably supported by a bearing block (not shown) fixed to the stationary base 60, and the other end is an output shaft drivingly connected to the pulse motor 832. Incidentally, a female screw block (not shown) is protruded below the central portion of the movable support portion 821 constituting the movable support base 82, and the male screw 831 is screwed with a female screw hole formed in the female screw block. Therefore, the male screw 831 can be driven forward and reverse by the pulse motor 832, thereby moving the movable support base 82 along the guide rails 81 and 81 in the index feeding direction shown by the arrow Y (Y axis Direction).

The laser light irradiation unit 9 in the illustrated embodiment includes a unit holder 91 and a laser light irradiation means 92 attached to the unit holder 91. The unit holder 91 is provided with slidably fitted guide grooves 911 and 911 of one pair of guide rails 823 and 823 provided in the attachment portion 822, and guides the guide The grooves 911 and 911 are fitted into the guide rails 823 and 823 and are supported so as to be movable in the Z-axis direction.

The laser light irradiation unit 9 in the illustrated embodiment includes a light spot position adjusting means 93 for moving the unit holder 91 along the pair of guide rails 823 and 823 in the Z-axis direction. The focusing point position adjusting means 93 includes a driving screw (not shown) fitted between a pair of guide rails 823 and 823, and a driving source such as a pulse motor 932 for rotationally driving the male screw. The pulse motor 932 drives a male screw (not shown) to rotate forward and reverse, thereby moving the unit holder 91 and the laser light irradiation means 92 along the guide rails 823 and 823 in the Z-axis direction. Incidentally, the implementation in the illustration In the form, the laser beam irradiating means 92 is moved upward by driving the pulse motor 932 in a forward direction, and the laser beam irradiating means 92 is moved downward by driving the pulse motor 932 in a reverse direction.

The illustrated laser light irradiation means 92 includes a cylindrical housing 921 fixed to the unit holder 91 and extending substantially horizontally. The laser light irradiation means 92 will be described with reference to FIG. 8.

The laser light irradiation means 92 shown in the figure includes: a pulse laser light oscillating means 922, which is assembled in the casing 921; and an output adjustment means 923, which adjusts the pulse laser light Output; the condenser 924 irradiates the pulsed laser light whose output is adjusted by the output adjustment means 923 toward the workpiece W held on the holding surface of the chuck table 76.

The above-mentioned pulse laser light oscillating means 922 is a pulse laser ray oscillator 922a that oscillates a pulse laser ray, and a repeated frequency setting means 922b that sets the repeated frequency of the pulse laser ray oscillated by the pulse laser ray oscillator 922a. Make up. The output adjusting means 923 adjusts the output of the pulsed laser light oscillated by the pulsed laser ray oscillating means 922 to a predetermined output. The pulsed laser light oscillator 922a, the repeated frequency setting means 922b, and the output adjustment means 923 of the pulsed laser light oscillation means 922 are controlled by control means (not shown) described later.

The condenser 924 has a direction conversion mirror 924a and a condenser lens 924b. The direction conversion mirror 924a oscillates the pulsed laser light oscillating means 922 and outputs the pulsed laser light adjusted by the output adjustment means 923 to the chuck table 76. The holding surface changes direction, and the condenser lens 924b is subject to the The pulsed laser light after the direction conversion mirror 924a changes the direction condenses and irradiates the workpiece W held on the chuck table 76. The condenser 924 thus constructed is attached to the front end of the housing 921 as shown in FIG. 7.

As shown in FIG. 7, a photographing means 95 is mounted on a front end portion of the housing 921 constituting the laser light irradiation means 92, and the photographing means 95 detects a processing area where laser processing should be performed by the laser light irradiation means 92. The photographing means 95 is constituted by optical means such as a microscope or a CCD camera, and transmits a photographed image signal to a control means described later.

With reference to FIG. 8, the laser processing device 6 in the illustrated embodiment has a plasma detection means 96 that is mounted on the laser light irradiation means 92 constituting the laser light irradiation unit 9. The housing 921 detects the plasma generated by the laser light irradiated by the laser light irradiation means 92 to the workpiece held on the chuck table 76. The plasma detecting means 96 is formed by a plasma receiving means 961, a band-pass filter 962, and a light detector 963. The plasma receiving means 961 receives a laser beam irradiated by the condenser 924 of the laser light irradiation means 92. Plasma generated when light is irradiated to the workpiece W held on the chuck table 76; a band-pass filter 962 corresponds to a setting substance (for example, silicon (Si)) in the plasma light received by the plasma receiving means 961 ) Of the plasma (251 nm), and only allows light with a wavelength of 245 to 255 nm to pass through; the photodetector 963 receives the light passing through the band-pass filter 962 and outputs a light intensity signal. The above-mentioned plasma receiving means 961 is composed of a condenser lens 961a and a lens box 961b that houses the 961a. The lens box 961b is a housing 921 that is mounted on the laser light irradiation means 92 as shown in FIG. The photodetector 963 of the plasma detection means 96 configured in this way matches the intensity of the received light The corresponding voltage signal is output to the control means described later.

The laser processing apparatus in the illustrated embodiment includes the control means 10 shown in FIG. 9. The control means 10 is composed of a computer, and has a central processing unit (CPU) 101 that performs calculation processing in accordance with a control program, a read-only memory (ROM) 102 that stores control programs and the like, and a control chart or a processed object described later The readable and writable random access memory (RAM) 103, the input interface 104 and the output interface 105 are stored in the design value data or calculation results. The detection signals from the X-axis direction position detection means 774, the Y-axis direction position detection means 784, the photographing means 95, and the light detector 963 of the plasma detection means 96 are input to the input interface 104 of the control means 10. In addition, a control signal is output from the output interface 105 of the control means 10 to the pulse motor 772, the pulse motor 782, the pulse motor 832, the pulse motor 932, and the pulse laser of the pulse laser light oscillation means 922 constituting the laser light irradiation means 92. The radiation oscillator 922a, the repeated frequency setting means 922b, the output adjustment means 923, the display means 100, and the like. Incidentally, the random access memory (RAM) 103 has a defective processing information storage area 103a that stores the coordinate values of the defective processing portions of the workpiece.

The laser processing device 6 in the illustrated embodiment is configured as described above. The laser processing device 6 is used to attach a film (DAF) attached to the back surface of the semiconductor wafer 2 that has been subjected to the wafer support step described above. A step of dividing the film along the dividing groove 210 and then dividing the film will be described.

The semiconductor wafer 2 which is subjected to the wafer supporting step and is supported by the ring frame F across the dicing tape T is placed on the chuck table 76 of the laser processing apparatus 6 shown in FIG. 7. Then, the unillustrated attraction means is As a result, the semiconductor wafer 2 is sucked and held on the chuck table 76 via the dicing tape T. Therefore, the semiconductor wafer 2 is held so that the surface is on the upper side. The ring frame F is fixed by the clamper 762.

The chuck table 76 that sucks and holds the semiconductor wafer 2 as described above is positioned under the imaging means 95 by the processing feed means 77. When the chuck table 76 is positioned directly under the photographing means 95, the semiconductor wafer 2 on the chuck table 76 is positioned in the coordinate position shown in FIG. In this state, the imaging means 95 is operated, the processing feed means 77 and the first indexing feed means 78 are operated, and the chuck table 76 is moved to detect the semiconductor wafer 2 held by the chuck table 76. For all the divided grooves 210 formed, the control means 10 stores the coordinate values of all the divided grooves 210 in the random access memory based on the detection signals from the X-axis direction position detection means 774 and the Y-axis direction position detection means 784. (RAM) 103 (correction step).

Next, as shown in FIG. 11 (a), the semiconductor wafer 2 held by the chuck table 76 via the dicing tape T is moved to the laser light irradiation area where the condenser 924 is located, and the predetermined division is divided. The trench 210 is positioned directly below the condenser 924. Next, the control means 10 outputs a control signal to the laser light irradiation means 92 to irradiate a pulsed laser light having a wavelength which is absorptive to the adhesive film (DAF) from the condenser 924, and controls the processing feed means 77 to make the clamp The head table 76 is moved in a direction indicated by an arrow X1 in FIG. 11 (a) at a predetermined processing feed rate. Then, when the other end of the dividing groove 210 reaches the position directly below the condenser 924 as shown in FIG. 11 (b), the irradiation of the pulse laser light is stopped and the movement of the chuck table 76 is stopped. As a result, pulsed laser light The adhesive film DAF is irradiated through a predetermined division groove 210, and the cutting film DAF is formed along the division groove 210 as shown in FIG. 11 (c) (a subsequent film division step).

For example, the processing conditions following the film division step are set as follows.

Light source: LD excitation Q switching Nd: YVO4 pulse laser

Wavelength: 355nm

Repeated frequency: 50kHz

Average output: 2W

Condensing spot diameter: φ10μm

Processing feed speed: 300mm / s

When the above-mentioned subsequent film division step is performed, if the gap between the division grooves 210 formed in the semiconductor wafer 2 is insufficient, or the element 22 protrudes toward the division groove 210 side, a part of the laser light will be blocked by the element 22, Then the film (DAF) is not cut. In order to grasp the portion where the adhesive film (DAF) is not cut, the control means 10 activates the plasma detection means 96 when performing the adhesive film division step. In this subsequent film division step, the control means 10 inputs a light intensity signal from the light detector 963 of the plasma detection means 96. In the subsequent film splitting step, when the pulsed laser light irradiated from the condenser 924 is irradiated to the bonding film (DAF) through the splitting groove 210, Although the wavelength will be received by the plasma receiving means 961, it is not possible to pass the bandpass filter 962 to 245 ~ 255nm, so it cannot pass the bandpass filter 962. On the other hand, if The element 22 protrudes toward the dividing trench 210 side, and pulsed laser light irradiates the element 22. Since the element 22 is formed of silicon, plasma light having a wavelength of 251 nm is generated. Therefore, since the plasma light having a wavelength of 251 nm received by the plasma receiving means 961 passes through the band-pass filter 962 and reaches the photodetector 963, the photodetector 963 directs a voltage signal corresponding to the received light intensity toward the control means 10 Send. The control means 10 judges that the signal transmitted from the photodetector 963 is based on the plasma of the element 22 made of a silicon wafer. Then, based on the detection signals from the X-axis direction position detection means 774 and the Y-axis direction position detection means 784, the control means 10 stores the coordinate values when a voltage signal corresponding to the light intensity received by the photodetector 963 is output at random. The memory (RAM) 103 is accessed as the defective machining coordinate value (the defective machining coordinate value detection step).

The step of dividing the next film is performed as described above, and the pulsed laser light is irradiated to the adhesion film (DAF) through all the division grooves 210 formed in a predetermined direction, and a cutting groove is formed in the adhesion film (DAF) along the division groove 210. After G, the control means 10 actuates the first indexing feed means 78, and moves the chuck table 76 in the direction shown by the arrow Y in FIG. 7 so that the adjacent dividing groove 210 is positioned directly below the condenser 924. The above-mentioned subsequent film division step is performed. In this way, the step of performing the film splitting step is performed to irradiate the pulsed laser light through the dividing groove 210 formed in a predetermined direction to the film of the adhering film (DAF), then the chuck table 76 is rotated 90 degrees, and the step of performing the film splitting step is performed to pulse the laser. The light is irradiated to the adhesive film (DAF) through the division groove 210 formed in a direction orthogonal to the predetermined direction. In this way, the subsequent film division step is performed to irradiate the pulsed laser light through the entire division grooves 210 formed in the semiconductor wafer 2 to the adhesion film. In the case of (DAF), as described above, a step of detecting a defective coordinate value is performed, and the coordinate value of the portion where the film (DAF) is not cut is stored in the defective defective information grid region 103a of the random access memory (RAM) 103. In addition, the coordinate value of the portion where the adhesive film (DAF) is not cut in the defective processing information Genna region 103a stored in the random access memory (RAM) 103 is displayed on the display means 100 as processing defective information.

As described above, the coordinate values displayed on the portion where the adhesive film (DAF) of the display means 100 is not cut as the processing defect information can be used in the picking step of the next step, thereby eliminating the problem that the component cannot be picked up together with the adhesive film.

In addition, based on the coordinate values of the portion where the adhesive film (DAF) of the display means 100 is not cut as the information on the processing failure, the component in the processing failure area can be photographed to check the cause of the processing failure.

Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, although it has been shown that the plasma detecting means in the above embodiment is formed by the plasma receiving means 961, the band-pass filter 962, and the light detector 963 and the plasma receiving means 961 receives An example of the plasma and band-pass filter 962 generated from the processed object W is to pass only the light of the set wavelength of the plasma, and the photodetector 963 receives the light passing through the band-pass filter 962 to output the light intensity signal. However, the following detection methods can also be used.

(1) The above-mentioned band-pass filter is not used. When the light intensity of the plasma detected by the photodetector reaches a predetermined value, it is determined to be abnormal.

(2) In the method of (1) above, due to the oscillation wavelength of the irradiated laser This can be a hindrance, so a photodetector is installed behind a filter that blocks only the wavelength (for example, 355nm) of the irradiated laser to detect the plasma.

(3) Plasma is detected by staggering the oscillation timing of the pulse of the irradiated pulse laser. Incidentally, although the influence of the irradiated laser can be reduced in this method, a filter that blocks only the wavelength (for example, 355 nm) of the irradiated laser should be installed before the photodetector.

2‧‧‧ semiconductor wafer

2a‧‧‧ surface

2b‧‧‧ back

22‧‧‧ Components

210‧‧‧ divided trench

76‧‧‧ Collet Worktable

924‧‧‧ Concentrator

DAF‧‧‧ Adhesive film

G‧‧‧cut trench

T‧‧‧Cutting Tape

X1‧‧‧arrow

Claims (2)

A wafer processing method is to divide a wafer having a plurality of scribe lines in a grid shape on the surface and forming a component in a plurality of areas divided by the plurality of scribe lines into individual components along the scribe lines, and divide each component in each component. The backside attaching adhesive film is characterized in that it includes the following steps: a dividing groove forming step, forming a dividing groove having a depth corresponding to the processing thickness of the element along the dicing path from the surface side of the wafer; a protective member attaching step, The protective member is attached to the surface of the wafer that has been subjected to the dividing groove forming step; the wafer dividing step is to grind the back surface of the wafer that has been subjected to the protecting member attaching step so that the divided groove appears on the back, and the crystal The circle is divided into individual components. In the wafer supporting step, the adhesive film is attached to the back of the wafer that has been subjected to the wafer dividing step. A dicing tape is attached to the adhesive film side and the dicing tape is supported by a ring frame. At the outer periphery, the protective member attached to the surface of the wafer is peeled off. Next, the film dividing step is to hold the dicing tape side of the wafer to which the wafer supporting step has been applied. The workpiece holding means of the laser processing device irradiates laser light from the surface side of the wafer through the dividing groove to the adhesive film, thereby dividing the adhesive film along the dividing groove; the adhesive film dividing step is The plasma light generated when laser light is irradiated is detected, and the coordinate value when the plasma light generated by laser light irradiated to the component is detected is recorded. A laser processing apparatus includes a workpiece holding means for holding a wafer, and the wafer is formed by a plurality of regions divided by a plurality of regions divided by a plurality of scribe lines formed on a surface of a grid. Dividing grooves along the dicing path are divided into individual elements, and a bonding film for die bonding is attached to the back side; laser light irradiation means, from the wafer held by the workpiece holding means Along the dividing groove, laser light is irradiated onto the adhesive film along the dividing groove; and the processing feed means moves the workpiece holding means and the laser light irradiation means relative to each other in the processing feed direction (X-axis direction). Indexing feed means to move the workpiece holding means and the laser light irradiation means relative to the indexing feed direction (Y-axis direction) orthogonal to the processing feed direction (X-axis direction); X Axial position detection means detects the X-axis position of the object holding means; a Y-axis position detecting means detects the Y-axis position of the object holding means; a photographing means holds the object means The wafer should be processed to divide the groove for shooting; the laser processing device is characterized by having a plasma detection means and a control means, the aforementioned plasma detection means is used to detect when the laser light is maintained along the substrate. When the divided grooves of the wafer of the processed object holding means irradiate the adhesive film, plasma light generated by irradiating the laser light to the wafer; the control means includes a light source based on the plasma detection means, the The detection signals of the position detection means in the X-axis direction and the position detection means in the Y-axis direction record a memory in which the coordinate values of the plasma light generated by the plasma detection means are recorded, and the borrowing is detected by the plasma detection means. By Ray In the case of plasma light generated by irradiating the wafer with light rays, the coordinate values for generating plasma light are obtained based on the detection signals from the X-axis direction position detection means and the Y-axis direction position detection means. The coordinate value of the plasma light is recorded in the memory as the coordinate value of the machining defect.